It is more common for business's representative accounts to buy Copper membership and start their posts easily with graphics, images. It's less common for people who are not from any business to buy Copper membership, there are but not too popular.
I don't think so
(IMO), there are several or number of legendary
(and other higher than full member) who bought copper membership just for fun or for additional "label or badge" on its profile.
But, yes, that paid membership rank is intended for low rank users who want to bypass account limitations, more precisely for service's representative account.